1. Field of the Invention
The present invention generally relates to virtual meetings including presentations provided over a computer network and, more particularly, to the synchronization of display of visual images used in such presentations at terminals connected to the network.
2. Description of the Prior Art
In the past, meetings have been considered to be essential for business and educational purposes and the like where presentations are often made to convey information graphically to participants for supplementing an oral discussion being conducted by a presenter. Currently, to accommodate a potentially wide geographic distribution of desired participants and a greatly increased number and frequency of such meetings, communication arrangements (e.g. IBM's e-meeting tool) for supporting virtual meetings have been developed and range for telephone conference calls where an arbitrary but usually relatively small number of participants essentially share a voice line to complex presentations including visual materials to be presented using PowerPoint™ systems or the like for broadcast over a digital data network to a large number of individuals.
In the latter type of virtual meetings, it is desirable to allow the user/participant to exercise as great a degree of freedom as possible in viewing the visual materials although such a facility is not provided by all e-meeting tools. For example, while the visual materials will generally be arranged in a linear and non-branching sequence of images (referred to hereinafter as foils, frames or, more commonly, pages), each having an identifier such as one of a sequence of numbers, letters or the like associated therewith, which can be traversed by the presenter either incrementally in a forward or backward direction or by directly proceeding (sometimes referred to as a “jump”) to a particular foil or frame by a “go to” command, the users may wish to review or take notes (generally using a different application, requiring the user to shift back and forth between that application and the e-meeting tool) in regard to a particular foil/frame other than the one being discussed by the presenter and facilities supporting such user activities are provided in some, but not all, e-meeting systems.
However, where such facilities are provided, they often lead to confusion of the user in following the presentation when the presenter changes the current page while the user is viewing a different page. That is, while it would be a simple matter to track a departure of a user from a current page being discussed by a presenter and reverse the sequence to return to the page being presented at the time of the departure from the presenter's sequence, tracking the presenter's changes after the departure is much more complicated and the user generally has no frame of reference for navigating to a current page manually and ascertaining that it is the presenter's current page (thus presenting a severe distraction from the presentation in order to attempt to do so). Further, the presentation of a new page may cause the user to seek to pre-empt review of note-taking in regard to the page to which the departure was taken.
Alternatively, the presenter may wish to be certain that all participants have a view of a particular page at one or more points in the presentation. For this reason, synchronization of the image provided to the user with the page changes controlled by the presented is provided in some e-meeting tools by sending the presenter's image change commands to the participants as part of the presentation. However, while page changes made by the presenter may be transmitted as part of the virtual meeting, it is not practical to track the potential departures of all users and to transmit individualized commands when the presenter changes pages or to transmit the actual pages as the presenter changes pages since either procedure would greatly increase processing at the presenter's terminal and transmission overhead, particularly for current page transmission which cannot be done in real time and variation in transmission delays may also be a source of similar user confusion. All of the above distractions and sources of confusion are exacerbated when the user participates from a regular business terminal which may also present pop-up chat items, telephone messages (e.g. voice over internet protocol), e-mail arrival announcements and the like may occur. At the current state of the art, no solution to these problems exist which are consistent with a user's freedom to browse the presenter's pages.